A Welshman was among the three British servicemen killed in an ambush in Iraq.

He was named as Corporal Dewi Pritchard, 35, a married Territorial Army soldier, from Bridgend, South Wales.of 116 Provost Company.

The three Royal Military Police were all serving with the 19 Mechanised Brigade.

Gunshots were fired at them early on Saturday morning as they made their way through a main street in an armed convoy of two vehicles.

A fourth soldier is in hospital with serious injuries following the assault, which came less than a fortnight after the death of another British soldier in the area.

The other dead were named by the Ministry of Defence as Major Matthew Titchener and Warrant Officer Colin Wall, both of 150 Provost Company.

The killings are a further blow for the Royal Military Police (RMP), which suffered its worst casualty toll for more than 50 years in June, when six soldiers were killed.

As an investigation was launched into the deaths, Prime Minister Tony Blair was being kept informed at his country residence, Chequers.

A Downing Street spokesman said: "Our thoughts are with the families at this time. This again shows the courage and risks taken by our armed forces to build a better Iraq."

The attack happened as the uniformed soldiers, who were armed, made a routine journey through Basra at around 8.30am local time (5.30am UK time), the Ministry of Defence said.

Meanwhile, nearly 300 miles away, British diplomats had left their Baghdad embassy following a "credible threat" of attack.

Reports at the scene in Basra said a bomb was thrown at the troops from a red pick-up truck but the MoD said there was no evidence yet to suggest such a device was used. An MoD spokeswoman in the port city said: "A convoy of two vehicles was travelling through Basra in a routine movement when they were ambushed by gunmen from a pick-up truck. The convoy consisted of one military Land Rover and a civilian four wheel drive. All members of the convoy were wearing military uniforms and were armed. Three soldiers were killed and one seriously injured in the unprovoked attack. An investigation has been started."